The invention relates to a method and apparatus for controlling a yarn winding machine of the type wherein a continuously advancing yarn is wound on a tube to form a yarn package.
A yarn winding or takeup machine is known wherein at an increasing package diameter the distance between the axis of a contact roll and the axis of a winding spindle is enlarged by rotating a turret which mounts the winding spindle. Note for example, DE 40 18 095 and corresponding U.S. Pat. No. 5,100,072. In this known machine, the contact roll lies against the circumference of the package and is mounted such that it is able to perform during the winding operation a radially directed movement relative to the package surface. The lift of the contact roll is detected and supplied to a turret control, which activates a drive of the turret such that the contact roll maintains a predetermined desired position during the winding operation.
In the above method, the contact roll performs the movement of a pendulum about its desired position. Based on bearing tolerances as well as geometrical transmission ratios, a certain deflection of the contact roll is necessary to obtain a utilizable signal for controlling the journal drive.
It is the object of the present invention to detect the increase of the package diameter directly so as to permit a change in position of the winding spindle relative to the contact roll, without substantially changing the position of the winding spindle and the contact roll relative to each other.
A further object of the invention is to provide a simple and compact control system for a yarn winding machine.